This invention relates, in general, to multiple integrated circuits in a single package, and more particularly, to leadframe packages containing more than one high frequency component.
Circuits which are fabricated using many discrete elements are still con,on. A voltage controlled oscillator (VCO) is one such circuit. Some of the components needed to build the VCO cannot be fabricated on existing semiconductor process flows. Thus the VCO must be built using several components.
Many discrete versions of voltage controlled oscillators are being sold for general applications. The VCO's are built from components which are coupled together on one or more printed circuit boards. VCO's are sensitive to radio frequency (RF) noise so the printed circuit boards are placed in a metal cannister for RF noise isolation with terminals exposed for mounting on a printed circuit board. The physical size of the entire VCO can be quite large. How much board space a component takes can be quite critical with todays trends towards increased functionality and miniaturization. Also, a VCO's ability to handle shock and environmental changes may be critical to an application.
Building a discrete version of a VCO involves the purchase of separate components and maintaining an inventory to fabricate circuits. Fabrication of a discrete version will result in yield losses which can be attributed to faulty individual components, printed circuit board errors, assembly errors, and package fabrication errors. The discrete VCO can be expensive to manufacture. Performance may also be a factor which might not be attained using discrete components. It would be of great benefit to provide a VCO in a single integrated circuit package using a minimum number of components which reduces costs, simplifies fabrication, is smaller in size, is resistant to vibration affects, yields well due to higher integration levels, and is shielded from radio frequency noise.